1. Field of the Invention
This invention relates to a steel framing system for multi-story building structures.
More particularly, the invention concerns an improved framing system for steel-concrete building structures.
In still another respect the invention relates to such framing systems in which seismic loads and bearing loads are transmitted by steel-to-steel contact between structural elements of the load bearing walls.
In yet another and more particular aspect the invention concerns a framing system for multi-story steel-concrete building structures for constructing expandable, inexpensive buildings by the use of semi-skilled or unskilled labor.
In a further and more particular respect the invention pertains to such systems, the use of which permits construction work to proceed without waiting for concrete floor slabs to cure fully.
In yet another and still more particular aspect the invention pertains to framing systems which permit the installation of steel-concrete building structures having improved fire ratings.
2. Description of the Prior Art
In the construction of multi-story buildings such as office buildings, motels and the like, it is common practice to successively erect bearing walls, place steel forms on these walls, pour a concrete floor in the supported forms, erect the bearing walls for the next story, place the forms and pour the next higher floor and so on until the basic structure of the building is completed.
According to one method, the bearing walls are constructed with horizontally spaced steel studs or framing members supported by the floor below with exterior and interior wall facings affixed to these studs as the construction proceeds. According to this method, embods are set into the concrete floors for attaching steel channels which locate the metal studs of the next higher floor and for supporting and for locating other elements of the structure such as exterior curtain walls, lintels and the like.
Although the above-described construction methods offer significant economies in comparison to other methods of building construction, there still exists significant practical and economic problems in the use of such methods. For example, the progress of the construction is slowed by the need to wait until each poured concrete floor develops significant and sufficient strength by curing to permit the floor to support the bearing walls of the next structure and the weight of the next poured floors and walls. Also, the placement of the weldments in the poured floors requires considerable time and expertise to insure that the steel components of the next-upper floor are properly aligned. Furthermore, virtually all construction codes require that the steel elements be shielded by a thermal insulation barrier to achieve a preselected "fire rating", usually expressed as the number of hours of exposure to fire without failure of the structural integrity of the building. This requirement, in turn, dictates that any steel elements used to interconnect the bearing walls and the poured floors be either embedded in concrete or covered by hand-placed insulation materials. These insulation steps further complicate, delay and make the overall construction cost considerably higher as they normally require significant hand labor operations.
It would be highly desirable to provide an improved steel framing system for multi-story building structures in which the time for installation of the building components is reduced, in which the installation can be accomplished by semi-skilled and unskilled labor and in which the use of hand-labor operations to achieve the necessary fire rating is minimized or practically eliminated.
Accordingly, the principal object of the present invention is to provide such an improved framing system for steel-concrete building structures.
A further and more particular object of the invention is to provide such a framing system in which the bearing walls provide for the direct transmission of loads by steel-to-steel contact between the structural elements of the bearing walls, so as to reduce the time delays previously encountered in waiting for each poured concrete floor to cure sufficiently to support the next-above bearing walls and poured floor.
Still another and more particular object of the invention is to provide such an improved framing system for such buildings in which the need for setting weldments in the poured concrete floors is substantially reduced or eliminated.
Still another object of the invention is to provide such framing system which will permit the construction of buildings with the requisite fire rating with a reduced amount of hand labor.
Still another, further and more particular object of the invention is to provide such systems in which the finished building is considerably less expensive, has the desired fire rating and improved seismic load capabilities in comparison to conventional buildings in which such loads are not transmitted by direct steel-to-steel contact of structural elements in the bearing walls.